To provide a chemical ablation device that enables simple performance of chemical ablation treatment including pre- and post-treatment potential measurements. A chemical ablation device according to the present invention includes an electrode-equipped guidewire (30) with which intracardiac potential is measurable, an over-the-wire balloon catheter (40) having a guidewire lumen (415) into which the electrode-equipped guidewire (30) is to be inserted, a Y-shaped connector (50) connected to a proximal side of the balloon catheter (40) and including a guidewire port (51) and an expansion port (53), and a hemostasis valve (60) connected to the guidewire port (51) of the Y-shaped connector (50) and including a side-infusion tube (65) for supplying ethanol to the guidewire lumen (415) of the balloon catheter (40). The ethanol supplied to the guidewire lumen (415) of the balloon catheter (40) is ejected from an opening of a distal tip (47).
